EP0070148B1 - Method and apparatus for monitoring particles in a liquid medium - Google Patents
Method and apparatus for monitoring particles in a liquid medium Download PDFInfo
- Publication number
- EP0070148B1 EP0070148B1 EP82303574A EP82303574A EP0070148B1 EP 0070148 B1 EP0070148 B1 EP 0070148B1 EP 82303574 A EP82303574 A EP 82303574A EP 82303574 A EP82303574 A EP 82303574A EP 0070148 B1 EP0070148 B1 EP 0070148B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- substrate
- particles
- liquid medium
- magnetic field
- axis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
- G01N15/02—Investigating particle size or size distribution
- G01N15/0266—Investigating particle size or size distribution with electrical classification
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/26—Oils; viscous liquids; paints; inks
- G01N33/28—Oils, i.e. hydrocarbon liquids
- G01N33/2835—Oils, i.e. hydrocarbon liquids specific substances contained in the oil or fuel
- G01N33/2858—Oils, i.e. hydrocarbon liquids specific substances contained in the oil or fuel metal particles
Definitions
- This invention relates to a method and apparatus for monitoring magnetically polarised or polarisable particles which are initially suspended in a liquid medium but deposited for monitoring purposes onto a suitable substrate.
- the invention has particular, but not exclusive, application to the analysis of wear particles in the lubricating medium of an engine or other machine.
- a conventional "Ferrograph” uses a slightly inclined stationary flat glass microscope slide to receive the deposit, the liquid medium being allowed to flow under the influence of gravity through an intense magnetic field from a medium application point located at arrupper region of the- slide.
- a substantial proportion (by weight) of the particles deposited in a typical "Ferrogram” remain on the slide close to the application point so that this region can become over congested with particles before desirably dense deposits have formed in lower regions. In general it is the larger particles that deposit first from the flow of medium down the slide adding to the congestion of particles in the vicinity of the application point.
- GB-A-1300309 discloses a method of and apparatus for separating particles of magnetic material from a liquid carrying medium.
- a disc-like separation member rotates relative to an underlying array of one or more magnets as the liquid medium flows down over the member. The separated particles are removed from the member in a region where there are no underlying magnets.
- a method of monitoring magnetically polarised or polarisable particles carried in a liquid medium comprising impinging a flow of said liquid medium onto the upper surface of a horizontal or substantially horizontal substrate located in a magnetic field having a component extending generally at right angles to said surface for depositing said particles onto the surface, removing the substrate from the magnetic field and optically monitoring said deposited particles, which is characterised in that said substrate is rotated about an axis, passing through said substrate and disposed generally parallel to said component of the magnetic field without relative motion between said magnetic field and said substrate, at an angular speed sufficient to cause the rotation to modify the flow speed of said medium across said surface, and permit the magnetic field to cause said deposition of particles on the surface.
- the substrate can be a flat plate of optically transparent material and can be of any convenient shape or size.
- a square, circular or annular glass plate is preferred for this way of performing the method and a plate 0.1 mm or more thick with a maximum transverse dimension (e.g. diameter) of the upper surface in the range 25 to 50 mm (preferably 30 to 45 mm) is particularly convenient.
- a transparent sheet of optical quality material e.g. the sort of glass plate used for a microscope slide.
- One particular advantage of the method of the invention is that it can atlow the application point of the liquid medium to be extended into a circular application line surrounding the axis of rotation.
- This effect can be achieved in several ways.
- the centrifugal force generated by the rotation can be used as the sole transporting force acting on the medium resting on the said surface and in this case the medium would be applied to the substrate intermediate the axis of rotation and the outer edge(s) of the substrate and will flow radially outwards from the axis, to discharge over the edge(s).
- An annular plate can be used with the application line occurring close to the aperture in the plate.
- An alternative way of achieving a circular application line is to use a tunnel shaped substrate, and to select the rotational speed of the substrate so that the centrifugal force generated by the rotation is less than the gravitational force caused by the inwardly sloping gradient of the substrate.
- This alternative way makes the substrates more difficult to fabricate (and thus more expensive) and the control of the method more difficult, but it has the great advantage of permitting the deposit of particles to overlie substantially the entire upper surface from an application line close to the periphery to the medium discharge at the centre. Furtherthe expansion ofthe available deposit area is precisely as it is wanted, with the greatest area available for the largest particles first deposited and the smallest area for the hyperfine particles last to be deposited.
- the semi-angle of the frusto-conical substrate would desirably be in the range 85° to 89°.
- the flow rate of the liquid medium onto the substrate can vary widely depending on the viscosity of the medium, the range of sizes of particles to be separated therefrom and the strength of the magnetic field. Typical flow rates would lie in the range 1 to 20 ml/min with the middle of that range being most usual.
- the viscosity of the liquid medium will naturally depend on its source, but is not critical. In the case of lubricating oils it could lie anywhere between 10- 6 to 10- 3 m 2 /sec (1 cSt to 100 cSt) and can be lowered, if desired, with a suitable diluent.
- the rotational speed of the substrate can also vary widely depending on circumstances but can easily be optimised.
- One revolution per second gives satisfactory results for outwardly flowing medium on a flat substrate but speeds between- - - one quarter and four times this are contemplated.
- a deposit can be washed with a gentle flow of solvent in the manner well known in conventional "Ferrography", and the rotational speed can be increased to facilitate washing and draining.
- apparatus for producing a deposit pattern of magnetically polarised or polarisable particles on a substrate for subsequent monitoring, by extracting said particles from a liquid medium comprising supply means for feeding said liquid medium to a discharge opening thereof, a substrate having a horizontal or substantially horizontal surface disposed below said opening, and means to apply a magnetic field to the substrate so that a component of the field is generally orthogonal to the said surface and acts to draw the particles down onto said surface to form a deposit thereon, which is characterised in that means is provided to rotate the substrate, without inducing relative movement between the magnetic field and the substrate, about an axis passing through the substrate and substantially parallel to the said component of the magnetic field during creation of said deposit.
- the supply means does not mechanically compress the fluid medium (e.g. it does not include a peristaltic pump) since this can affect the size and/or shape of the particles.
- a carrier liquid e.g. an engine lubricant with or without organic diluent
- a carrier liquid e.g. an engine lubricant with or without organic diluent
- the axis of rotation is shown by the dash-dot line 7.
- the rotational speed is about 1 rev./sec.
- the carrier liquid moves radially outwards from its points of application to discharge over the edge of the disc 3 and be collected in the assembly 5.
- a cylindrical magnet 6 in the assembly 5 located just below the disc 3 gives rise to a strong field (about 4 x 10- 2 Weber/m 2 - 400 gauss) directed upwardly through the disc 3.
- the magnet 6 rotates with the disc 3. Since the disc 3 overlaps the magnet 6, the peripheral regions of the disc are in a weaker magnetic field than the central region so that there is a magnetic field gradient along each radial path followed by a particle in the carrier liquid from its point of application on the disc 3 to its deposit on the disc.
- Particles of different types are deposited at different radial positions, according to their size, density and magnetic susceptibility.
- the disc 3 is then removed from the assembly and examined microscopically.
- the innermost radial deposit is the densest but because it is spread out over a complete circle (e.g. of diameter 10 mm) there is not the congestion known at the application point of a conventional "Ferrogram".
- a liquid-tight seal of the disc 3 to the stem 4 is important to prevent carrier liquid (or its particles) staining the underside of the disc.
- a metal clip, temporary adhesive, rubber ring or partial vacuum can be used to seal the disc in place.
- the drive for the assembly can be from above, one side or below.
- Figure 2 is a "Ferrogram" (at x100 magnification) of a 1 ml sample of synthetic oil from a gear test machine diluted in the ratio 10:1 and
- Figure 3 is a further enlargement (at x400 magnification) of Figure 2 of an area close to the application point.
- Figure 4 is a modified "Ferrogram" (also at x100 magnification) of a similar sample to that used for the production of Figure 2 this time however the substrate had been rotated at 55 r.p.m. on an apparatus such as that shown in Figure 1.
- the line of application of the diluted sample is roughly represented by the chain line in Figure 4.
- Figure 5 is a further enlargement (at x400 magnification) of a region adjacent to the application line in Figure 4. The larger particles can be seen to be much more widely distributed and thus easier to analyse.
Abstract
Description
- This invention relates to a method and apparatus for monitoring magnetically polarised or polarisable particles which are initially suspended in a liquid medium but deposited for monitoring purposes onto a suitable substrate. The invention has particular, but not exclusive, application to the analysis of wear particles in the lubricating medium of an engine or other machine.
- It is known (e.g. from U.K. Patent 1415311) that magnetically or electrically polarised or polarisable particles suspended in a liquid medium can be made to deposit on a substrate by flowing the medium over the substrate in the presence of a magnetic or electric field. Under the correct deposit conditions, which inter alia depend on the medium, the field and the size, density and magnetic or electrical properties of the particles, the particles form a graded distribution on the substrate which facilitates their subsequent examination, e.g. by a densitometer or microscopically. Such a prior art graded deposit of magnetic particles is often referred to as a "Ferrogram", the apparatus for producing it as a "Ferrograph" and the science of wear particle analysis using such apparatus as "Ferrography".
- A conventional "Ferrograph" uses a slightly inclined stationary flat glass microscope slide to receive the deposit, the liquid medium being allowed to flow under the influence of gravity through an intense magnetic field from a medium application point located at arrupper region of the- slide. A substantial proportion (by weight) of the particles deposited in a typical "Ferrogram" remain on the slide close to the application point so that this region can become over congested with particles before desirably dense deposits have formed in lower regions. In general it is the larger particles that deposit first from the flow of medium down the slide adding to the congestion of particles in the vicinity of the application point. Further, to provide a controlled flow of medium over the slide, it is common practice to secure a generally U-shaped barrier on the upper surface of each slide used for a "Ferrogram", the bottom of the "U" passing above the application point and the limbs of the "U" extending down either side of the slide to define the medium flow channel therebetween. The cost of preparation of the slides with these barriers represents a significant part of the total cost of "Ferrography".
- GB-A-1300309 discloses a method of and apparatus for separating particles of magnetic material from a liquid carrying medium. In GB-A-1300309, a disc-like separation member rotates relative to an underlying array of one or more magnets as the liquid medium flows down over the member. The separated particles are removed from the member in a region where there are no underlying magnets.
- According to one aspect of the present invention there is provided a method of monitoring magnetically polarised or polarisable particles carried in a liquid medium, comprising impinging a flow of said liquid medium onto the upper surface of a horizontal or substantially horizontal substrate located in a magnetic field having a component extending generally at right angles to said surface for depositing said particles onto the surface, removing the substrate from the magnetic field and optically monitoring said deposited particles, which is characterised in that said substrate is rotated about an axis, passing through said substrate and disposed generally parallel to said component of the magnetic field without relative motion between said magnetic field and said substrate, at an angular speed sufficient to cause the rotation to modify the flow speed of said medium across said surface, and permit the magnetic field to cause said deposition of particles on the surface.
- According to one way of performing the method, the substrate can be a flat plate of optically transparent material and can be of any convenient shape or size. A square, circular or annular glass plate is preferred for this way of performing the method and a plate 0.1 mm or more thick with a maximum transverse dimension (e.g. diameter) of the upper surface in the range 25 to 50 mm (preferably 30 to 45 mm) is particularly convenient. Where the deposited particles are to be examined in situ on the substrate it is desirably a transparent sheet of optical quality material (e.g. the sort of glass plate used for a microscope slide).
- One particular advantage of the method of the invention is that it can atlow the application point of the liquid medium to be extended into a circular application line surrounding the axis of rotation. This effect can be achieved in several ways. For example, the centrifugal force generated by the rotation can be used as the sole transporting force acting on the medium resting on the said surface and in this case the medium would be applied to the substrate intermediate the axis of rotation and the outer edge(s) of the substrate and will flow radially outwards from the axis, to discharge over the edge(s). The greater the radial distance from the axis to the tube discharging the medium onto the said surface, the more extended the application line will become, but concomitantly the available area of the surface for the collection of deposited particles will become less for a given area of substrate surface. An annular plate can be used with the application line occurring close to the aperture in the plate.
- An alternative way of achieving a circular application line is to use a tunnel shaped substrate, and to select the rotational speed of the substrate so that the centrifugal force generated by the rotation is less than the gravitational force caused by the inwardly sloping gradient of the substrate. This alternative way makes the substrates more difficult to fabricate (and thus more expensive) and the control of the method more difficult, but it has the great advantage of permitting the deposit of particles to overlie substantially the entire upper surface from an application line close to the periphery to the medium discharge at the centre. Furtherthe expansion ofthe available deposit area is precisely as it is wanted, with the greatest area available for the largest particles first deposited and the smallest area for the hyperfine particles last to be deposited. The semi-angle of the frusto-conical substrate would desirably be in the range 85° to 89°.
- For wear particle analysis magnetic field strengths in the range 5 x 10-4 to 1 x 10-1 weber/m2 (5 to 1000 gauss) particularly 1 x 10-3 to 5 x 10-2 weber/m2 (10 to 500 gauss), would be typical. A cylindrical magnet axially aligned with the rotational axis of the substrate and disposed just below the latter is a convenient way of obtaining the required field, the magnet rotating with the substrate.
- The flow rate of the liquid medium onto the substrate can vary widely depending on the viscosity of the medium, the range of sizes of particles to be separated therefrom and the strength of the magnetic field. Typical flow rates would lie in the range 1 to 20 ml/min with the middle of that range being most usual.
- The viscosity of the liquid medium will naturally depend on its source, but is not critical. In the case of lubricating oils it could lie anywhere between 10-6 to 10-3 m2/sec (1 cSt to 100 cSt) and can be lowered, if desired, with a suitable diluent.
- The rotational speed of the substrate can also vary widely depending on circumstances but can easily be optimised. One revolution per second gives satisfactory results for outwardly flowing medium on a flat substrate but speeds between- - - one quarter and four times this are contemplated.
- To facilitate the optical monitoring, a deposit can be washed with a gentle flow of solvent in the manner well known in conventional "Ferrography", and the rotational speed can be increased to facilitate washing and draining.
- According to a further aspect of the invention there is provided apparatus for producing a deposit pattern of magnetically polarised or polarisable particles on a substrate for subsequent monitoring, by extracting said particles from a liquid medium, comprising supply means for feeding said liquid medium to a discharge opening thereof, a substrate having a horizontal or substantially horizontal surface disposed below said opening, and means to apply a magnetic field to the substrate so that a component of the field is generally orthogonal to the said surface and acts to draw the particles down onto said surface to form a deposit thereon, which is characterised in that means is provided to rotate the substrate, without inducing relative movement between the magnetic field and the substrate, about an axis passing through the substrate and substantially parallel to the said component of the magnetic field during creation of said deposit.
- Desirably the supply means does not mechanically compress the fluid medium (e.g. it does not include a peristaltic pump) since this can affect the size and/or shape of the particles.
- Other apparatus features can be deduced from the discussion of the method aspect of the invention given above.
- The invention will now be further described, by way of example, with reference to the accompanying drawings, in which:-
- Figure 1 is a schematic representation of one embodiment of apparatus according to the invention,
- Figures 2 and 3 are typical "Ferrograms" obtained on a conventional linear, gravity-assisted "Ferrograph" at two different magnifications, and
- Figures 4 and 5 are "Ferrograms" obtained on the apparatus sketched in Figure 1 also taken at two different magnifications.
- Referring to Figure 1, a carrier liquid (e.g. an engine lubricant with or without organic diluent) is expelled slowly from a tube 1 onto the flat- horizontal
upper surface 2 of athin glass disc 3 which is sealed in liquid-tight manner to atubular stem 4 of a rotatingassembly 5. The axis of rotation is shown by the dash-dot line 7. The rotational speed is about 1 rev./sec. - Due to centrifugal effects caused by the rotation, the carrier liquid moves radially outwards from its points of application to discharge over the edge of the
disc 3 and be collected in theassembly 5. - A
cylindrical magnet 6 in theassembly 5 located just below thedisc 3 gives rise to a strong field (about 4 x 10-2 Weber/m2 - 400 gauss) directed upwardly through thedisc 3. Themagnet 6 rotates with thedisc 3. Since thedisc 3 overlaps themagnet 6, the peripheral regions of the disc are in a weaker magnetic field than the central region so that there is a magnetic field gradient along each radial path followed by a particle in the carrier liquid from its point of application on thedisc 3 to its deposit on the disc. - Particles of different types are deposited at different radial positions, according to their size, density and magnetic susceptibility.
- After some 10 ml of carrier liquid have flowed over the disc (typically in a time of two or three minutes), the residual carrier liquid is washed off the disc leaving the particles where they were deposited.
- The
disc 3 is then removed from the assembly and examined microscopically. The innermost radial deposit is the densest but because it is spread out over a complete circle (e.g. of diameter 10 mm) there is not the congestion known at the application point of a conventional "Ferrogram". - A liquid-tight seal of the
disc 3 to thestem 4 is important to prevent carrier liquid (or its particles) staining the underside of the disc. A metal clip, temporary adhesive, rubber ring or partial vacuum can be used to seal the disc in place. - The drive for the assembly can be from above, one side or below.
- Figure 2 is a "Ferrogram" (at x100 magnification) of a 1 ml sample of synthetic oil from a gear test machine diluted in the ratio 10:1 and
- Figure 3 is a further enlargement (at x400 magnification) of Figure 2 of an area close to the application point.
- It will be noted how congested is the region around the application point and that even on the increased magnification of Figure 3 it is difficult to separate individual particles from the congested mass of particles. The actual photograph from which Figure 3 was produced was out of focus over substantial parts of the field of view indicating that the particles of wear debris were piled one on another.
- Figure 4 is a modified "Ferrogram" (also at x100 magnification) of a similar sample to that used for the production of Figure 2 this time however the substrate had been rotated at 55 r.p.m. on an apparatus such as that shown in Figure 1. The line of application of the diluted sample is roughly represented by the chain line in Figure 4. Figure 5 is a further enlargement (at x400 magnification) of a region adjacent to the application line in Figure 4. The larger particles can be seen to be much more widely distributed and thus easier to analyse.
Claims (11)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT82303574T ATE23751T1 (en) | 1981-07-09 | 1982-07-08 | METHOD AND DEVICE FOR DETECTING PARTICLES IN A LIQUID MEDIUM. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8121183 | 1981-07-09 | ||
GB8121183 | 1981-07-09 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0070148A1 EP0070148A1 (en) | 1983-01-19 |
EP0070148B1 true EP0070148B1 (en) | 1986-11-20 |
Family
ID=10523121
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP82303574A Expired EP0070148B1 (en) | 1981-07-09 | 1982-07-08 | Method and apparatus for monitoring particles in a liquid medium |
Country Status (8)
Country | Link |
---|---|
US (1) | US4500839A (en) |
EP (1) | EP0070148B1 (en) |
AT (1) | ATE23751T1 (en) |
AU (1) | AU558620B2 (en) |
CA (1) | CA1191723A (en) |
DE (1) | DE3274382D1 (en) |
DK (1) | DK306382A (en) |
GB (1) | GB2103358B (en) |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA1191723A (en) * | 1981-07-09 | 1985-08-13 | David G. Jones | Method and apparatus for monitoring particles in a liquid medium |
GB8329151D0 (en) * | 1983-11-01 | 1983-12-07 | Swansea University College Of | Rotary particle depositor |
GB2160655B (en) * | 1984-04-09 | 1989-05-24 | David Brian Jones | Method and apparatus for assessing particle deposits |
DE3583324D1 (en) * | 1984-04-09 | 1991-08-01 | Univ Swansea | METHOD FOR DETERMINING PARTICLE DEPOSITION. |
US4686469A (en) * | 1985-08-12 | 1987-08-11 | Tribometrics, Inc. | Method and device for measuring magnetic particles in a fluid |
US5708198A (en) * | 1994-03-17 | 1998-01-13 | Diagnetics, Inc. | Ferrous particle counter |
US5540089A (en) * | 1994-03-17 | 1996-07-30 | Diagnetics, Inc. | Ferrous particle collection apparatus |
US5604441A (en) * | 1995-03-14 | 1997-02-18 | Detroit Diesel Corporation | In-situ oil analyzer and methods of using same, particularly for continuous on-board analysis of diesel engine lubrication systems |
US6582661B1 (en) | 2000-06-30 | 2003-06-24 | Csi Technology, Inc. | Integrated lubricant analyzer |
US20050170354A1 (en) * | 2002-04-09 | 2005-08-04 | Danfoss A/S | Process for centrifugal distribution of liquid physiological specimens |
US7797986B2 (en) * | 2006-08-29 | 2010-09-21 | Spx Corporation | Magnetic fluid particulate separation process |
RU2484360C1 (en) * | 2012-01-11 | 2013-06-10 | Общество с ограниченной ответственностью "Газпром трансгаз Самара" | Gas transfer method (versions), and compressor station for its implementation (versions) |
CN107328828A (en) * | 2017-07-05 | 2017-11-07 | 厦门大学 | Aircraft engine oil chip is detected and analysis integrated design method and device |
CN110595963B (en) * | 2019-10-14 | 2024-03-22 | 中国矿业大学 | Online rotary ferrograph and equipment oil online monitoring method |
CN111558454B (en) * | 2020-06-18 | 2022-06-14 | 临朐鼎工磁电科技有限公司 | Dry magnetic separator and control method thereof |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1011664A (en) * | 1962-02-05 | 1965-12-01 | Commissariat Energie Atomique | Improvements in or relating to fission product detectors |
GB1300309A (en) * | 1970-09-16 | 1972-12-20 | British Titan Ltd | Separator |
GB2103358A (en) * | 1981-07-09 | 1983-02-16 | Oh Kwan Kwon | Method and apparatus for monitoring particles in a liquid medium |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3083830A (en) * | 1960-10-28 | 1963-04-02 | Alan T Broderick | Magnetic concentration of low grade ores containing magnetic ore minerals |
DE2241143B2 (en) * | 1971-08-25 | 1981-01-15 | The Foxboro Co., Foxboro, Mass. (V.St.A.) | Method and device for the investigation of particles suspended in a fluid |
US3823602A (en) * | 1972-11-20 | 1974-07-16 | Aluminum & Chem Corp | Sampling device |
US4047814A (en) * | 1974-02-27 | 1977-09-13 | Trans-Sonics, Incorporated | Method and apparatus for segregating particulate matter |
IT1044259B (en) * | 1975-03-21 | 1980-03-20 | Tropea M | DEVICE FOR CLASSIFYING THE GRANULOMETRY OF ANY DUSTY SUBSTANCE THROUGH CENTRIFUGATION |
JPS5224573A (en) * | 1975-08-19 | 1977-02-24 | Kobe Steel Ltd | Method and apparatus for measuring concentrations of fluorescent magnetic poder liquid |
GB2014062A (en) * | 1978-02-14 | 1979-08-22 | Brown R | Method and apparatus for separating mixtures or particulate solids |
-
1982
- 1982-07-07 CA CA000406791A patent/CA1191723A/en not_active Expired
- 1982-07-08 AU AU85736/82A patent/AU558620B2/en not_active Ceased
- 1982-07-08 AT AT82303574T patent/ATE23751T1/en not_active IP Right Cessation
- 1982-07-08 DK DK306382A patent/DK306382A/en not_active Application Discontinuation
- 1982-07-08 DE DE8282303574T patent/DE3274382D1/en not_active Expired
- 1982-07-08 GB GB08219859A patent/GB2103358B/en not_active Expired
- 1982-07-08 EP EP82303574A patent/EP0070148B1/en not_active Expired
- 1982-07-09 US US06/396,689 patent/US4500839A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1011664A (en) * | 1962-02-05 | 1965-12-01 | Commissariat Energie Atomique | Improvements in or relating to fission product detectors |
GB1300309A (en) * | 1970-09-16 | 1972-12-20 | British Titan Ltd | Separator |
GB2103358A (en) * | 1981-07-09 | 1983-02-16 | Oh Kwan Kwon | Method and apparatus for monitoring particles in a liquid medium |
Also Published As
Publication number | Publication date |
---|---|
ATE23751T1 (en) | 1986-12-15 |
AU558620B2 (en) | 1987-02-05 |
DE3274382D1 (en) | 1987-01-08 |
GB2103358A (en) | 1983-02-16 |
DK306382A (en) | 1983-01-10 |
EP0070148A1 (en) | 1983-01-19 |
US4500839A (en) | 1985-02-19 |
CA1191723A (en) | 1985-08-13 |
AU8573682A (en) | 1983-01-13 |
GB2103358B (en) | 1985-12-24 |
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